Process of providing uniform gloss,lacquer coated alkenyl aromatic resin article

ABSTRACT

Process of preparing articles from thermoplastic alkenyl aromatic resins having uniform gloss and chemical resistance by applying a lacquer coating to a substrate prepared from a blend consisting essentially of (1) from about 85 to 98 percent by weight of a thermoplastic alkenyl aromatic resin, and (2) from about 2 to 15 percent by weight of an essentially linear macromolecular olefin polymer containing from about 25 to about 50 percent by weight of chemically combined chlorine.

United States Patent [1 1 Bird et al.

[ PROCESS OF PROVIDING UNIFORM GLOSS, LACQUER COATED ALKENYL AROMATIC RESIN ARTICLE [75] Inventors: Arnett L. Bird; Ronald G. Lehrer;

John E. Mullen, all of Midland, Mich.

[73] Assignee: The Dow Chemical Company,

Midland, Mich.

[22] Filed: Nov. 17, 1971 [21] Appl. No.: 199,741

[52] US. Cl.ll7/l38.8 UA, l17/138.8 E, 260/876 B, 260/876 R, 260/897 C [51] Int. Cl B32b 27/06, B44d 5/00 [58] Field of Search 117/l38.8 E, 138.8 UA; 260/897 C, 889, 876 B, 876 R [56] References Cited UNITED STATES PATENTS 2,510,851 6/1950 Bacon et al 117/1388 X Nov. 20, 1973 3,494,982 2/1970 Grabowski et a] 260/897 X 3,578,484 5/1971 Walles et al. 117/47 FOREIGN PATENTS OR APPLICATIONS 827,543 2/ 1960 Great Britain Primary Examiner-William D. Martin Assistant ExaminerSadie L. Childs Att0rneyWilliam M. Yates et al.

[5 7 ABSTRACT 5 Claims, No Drawings PROCESS OF PROVIDING UNIFORM GLOSS, LACQUER COATED ALKENYLAROMATIC RESIN ARTICLE BACKGROUND OF THE INVENTION Blends of thermoplastic alkenyl aromatic resins with chlorinated olefin polymers are known, e.g., as described in US. Pat. No. 3,494,982, issued Feb. 10, 1970, which disclosed blends of ABS polymers with chlorinated polyethylene; British Pat. No. 827,543 published Feb. 10, 1960, which discloses blends of polystyrene with chlorinated polyethylene; and Japanese Pat. No. 13,255, issued in 1967, which disclosed blends of styrene-acrylonitrile copolymers with chlorinated polyethylene.

Heretofore, however, these prior known polymer blends have not been used to prepare lacquer coated shaped articles. Such articles have been prepared from the herein defined alkenyl aromatic resins but have been undesirably characterized by surface etching upon application of the lacquer coating with resulting loss of surface gloss. This effect is believed to be due to a stress relaxation, or deorientation of the polymer surface due to the action of the lacquer coating. It is the primary object of the present invention to provide uniform gloss lacquer coated articles prepared from alkenyl aromatic resins, i.e., articles wherein the alkenyl aromatic resin substrate is resistant to etching resulting from the application of conventional lacquer coatings.

SUMMARY The above and related objects are accomplished by utilization of a substrate material consisting essentially of l) from about 85 to 98 percent by weight of a thermoplastic alkenyl aromatic resin; and (2) from about 2 to percent by weight of an essentially linear macromolecular chlorinated olefin polymer containing from about 25 to about 50 percent by weight of chemically combined chlorine.

DESCRIPTION OF THE PREFEFFED EMBODIMENTS By an alkenyl aromatic resin is meant a solid polymer of one or more polymerizable alkenyl aromatic compounds wherein the polymer, copolymer or interpolymer comprises, in chemically combined form, at least about 40 percent by weight of at least one alkenyl aromatic compound having the general formula R A!(IJ=CHQ wherein Ar represents an aromatic hydrocarbon radical, or an aromatic holohydrocarbon radical of the benzene series containing up to 12 carbon atoms, and R is hydrogen or the methyl radical; and where any remainder comprises one or more olefinically unsaturated monomer copolymerized therewith.

Examples of such alkenyl aromatic monomers are styrene, a-methylstyrene,- o-methylstyrene, mmethylstyrene, p-methylstyrene, ar-ethylstyrene, arvinylxylene, ar-chlorostyrene, or ar-bromostyrene, tert- .butylstyrene and the like, which may have dissolved or dispersed therein rubbers such as polybutadiene rubber, either of the stereospecific or nonstereospecific variety, block copolymers of styrene and butadiene and like rubbers or polymeric materials employed for in creasing the impact resistance of styrene polymers. Particularly preferred materials include the ABS-type polymers, such as disclosed in U.S. Pat. No. 2,694,692, issued Nov. 16, 1954, and US. Pat. No. 3,555,119, issued Jan. 12, 1971; the copolymers of styrene and acrylonitrile, preferably those copolymers containing from about 65 to percent styrene and from about 35 to 20 percent acrylonitrile as disclosed by US. Pat. No. 2,739,142, issued Mar. 20, 1956; and polystyrene, the preparation of which is well known in the art.

The olefin polymers which are particularly adapted for chlorination and subsequent use in the present invention are those distinct species and varieties of essentially linear and unbranched highly porous polymers containing at least about mole percent ethylene in the polymer molecule with the remainder being one or more ethylenically unsaturated comonomers, such polymers being prepared under the influence of catalyst systems comprising admixtures of strong reducing agents such as triethyl aluminum and compounds of Groups IV-B, V-B and VI-B metals of the Periodic System, such as titanium tetrachloride, and the like, and having a molecular weight less than about 1,000,000 and preferably between about 20,000 and 30,000.

The polyolefins are readily chlorinated by practice of a chlorination procedure which comprehends the suspension chlorination in an inert medium of the described polyolefins, while in finely divided form, to a desired total of combined chlorine content, wherein such polymer is first chlorinated at a temperature below its agglomeration temperature for a period sufficient to provide a chlorine content of from about 2 to 23 percent chlorine, based on the total weight of the polymer; followed by the sequential suspension chlorination of such polymer for a period sufficient to provide a total chlorine content of from about 25 to 50 percent. Preferred process for preparing such chlorinated polyolefins are disclosed in US. Pat. No. 3,454,544, issued July 8, 1969.

The alkenyl aromatic resin and chlorinated olefin polymer can be admixed using any conventional technique including mechanical admixing in powder or molten form. A preferred method for preparing such polymer blends is the preparation of a concentrate of such materials containing from about 10 to 35 percent by weight of alkenyl aromatic resin and from about 90 to 65 percent by weight of chlorinated olefin polymer, followed by admixing such concentrate with additional amounts of alkenyl aromatic resin, e.g., by tumble blending, and subsequently forming injection molded plaques for subsequent application of the lacquer coating. It is to be understood that additional formulation additives can be used if desired, e.g., stabilizers and the like such as small amounts of stearic acid and pigments such as carbon black.

The lacquers which are subsequently coated on the alkenyl aromatic resin-chlorinated olefin polymer substrate may be any conventionally employed material including the nitrocellulose and acrylic type lacquers.

The articles of the present invention find particular use as uniform, high gloss, painted ladies shoe heels, and uniform gloss painted automotive instrument cluster housing and other automotive plastic parts; as packaging materials for food containing fats and oils; refrigeratorinner liners for improved chemical resistance to fats, oils and Freon gas, such as used as a blowing agent (1) an ABS resin containing about 25 percent by weight acrylonitrile, about 9 percent by weight of a (2) a polystyrene having a melt viscosity #7 poise of pared by injection molding one of several blends of l) 10 about 5,200; and an alkenyl aromatic resin (as hereinafter specifically (3) A copolymer of about 75 percent by weight stydescribed), and (2) a chlorinated polyethylene (CPE) rene and 25 percent by weight acrylonitrile having a having a chlorine content of about 25 percent by melt viscosity 1 poise of about 15,000.

Lacquers (B) Red Spot 300, Series SL 9440 black ABS lacquer with 25 percent SL 3316 thinner, (C) Acetone, and

TABLE I Alkenyl aromatic resin Coated surface OPE Lacgloss values Amount amount quer Type (percent) (percent) type Peak Slope The alkenyl aromatic resins and lacquers used are as follows:

Alkenyl Aromatic Resins block copolymer of about 30 percent by weight styrene and about 70 percent by weight butadiene, such ABS resin having a melt viscosity "/7 poise of about 18,000;

15 (A) Wurdack lacquer 4391-N,

(D) Methyl ethyl ketone.

in polyurethane foam; and as molded articles such as pipe and pipe fittings.

The invention is further illustrated but not limited by the following examples:

Example 1 In each of a series of experiments individual plaques measuring 4 inches in width by 1 1 inches in length and having a thickness of about 0.100 of an inch were preweight, an ultimate tensile strength of about 1500 psi, a 100 percent modulus of about 500 psi, and an elongation of about 900 percent. Each plaque was then individually coated with one of a series of clear lacquers and the surface gloss of each cdated surface determined using a Hunterlab Model D36 Distinctness of Exp. number Series I:

03680 -3893 814 87 3- 163 098 054 000 715 072 079 574 40:9 HWM O.

54004 68464. 83400 27400 267 277 120 146 031 781 050 110 LFU L L L& L 8 90w L7 L Lil LLZ QQZZ LOW 0 4 6 1mg.. N lmovmm 16%ww 13 M4 11 W 13 mmm %M% 11 11 1 1 0 m m m 099 M99 09% W99 W99 W99 W W 6.. 7.. 8.. 9.- 10. Series III Image clossmeier- This glossmeter ProvideS a numeri- The data from Table I illustrate the enhanced gloss cal value for what the eye sees with the peak readings provided by use of a substrate containing the desigbeing a measure of shininess and the slope reading a nated alkenyl aromatic resin in conbination with the measure of reflectance. The most shiny, glossy and rechlorinated polyethylene. Further, the coated samples flective plaques have the highest values. The following wherein the chlorinated polyethylene was not used ex- Table 1 sets forth the polymer blends and lacquers used hibited evidence of nonuniform relaxing of the surface, along with the peak and slope values described above. i.e., as small bumbs along the surface. By way of comparison, the articles desicrbed by the present invention were free from such defect and were characterized by an extremely uniform gloss. Similar good results as set forth herein were found utilizing chlorinated polyethylenes of the type described in Example I but containing 36 and 48 percent by weight of chemically combined chlorine. Further, substantially equivalent good results were obtained when utilizing preformed concentrates composed of from to percent by weight of the described ABS polymer with from 75 to 65 percent by weight of the des cr ilgaed chlorinated polyethylene, wherein such concentrates were blended with additional amounts of such ABS resin to provide blends containing 90 and 95 percent by weight of ABS. Example 2 In each of a series of additional experiments, individual test bars were prepared by injection molding one of several of the blends as set forth in Example 1. A surface of each test bar was then smeared with a mixture of 50 percent conttonseed oil and 50 percent oleic acid. Each test bar was then stressed at deflections of 1,500, 3,000 and 4,500 microinches for 24 hours. The ultimate elongation was then determined for each product and compared to the original elongation. This test is commonly used by the refrigeration industry to screen potential plastics for use as inner doors and food liners. The following Table II sets forth the compositions used and the testing results obtained;

uniform gloss lacquer coating thereon the improvement consisting of applying a lacquer coating to a substrate consisting essentially of a blend of 1) from about 85 to 98 percent by weight of said thermoplastic alkenyl aromatic resin, and (2) from about 2 to 15 per cent by weight of an essentially linear macromolecular olefin polymer containing from about 25 to about 50 percent by weight of chemically combined chlorine.

2. The process of claim 1 wherein said thermoplastic alkenyl aromatic resin is, in chemically combined form, at least about percent by weight of at least one alkenyl aromatic compound having the general formula:

Ar C=CH3 wherein Ar represents an aromatic hydrocarbon radical or an aromatic halohydrocarbon radical of the benzene series containing up to 12 carbon atoms and R is hydrogen or the methyl radical, with the remainder being one or more olefinically unsaturated monomer copolymerized therewith.

3. The process of claim 2 wherein said thermoplastic alkenyl aromatic resin is selected from the group consisting of: polystyrene, a copolymer of styrene and acrylonitrile, and an acrylonitrilebutadiene-styrene polymer.

4. The process of claim 1 wherein the chlorinated olefin polymer is chlorinated polyethylene.

The data from Table ll illustrates that the articles of the present invention are substantially uneffected by the exposure to the cottonseed oil oleic acid mixture.

What is claimed is:

1. In the process of preparing articles from thermoplastic alkenyl aromatic resins said articles having a 5. The process of claim 4 wherein the chlorinated polyethylene has a molecular weight of from about 20,000 and 300,000 and has a crystallinity of less than about 10 percent when containing about 34 or more weight percent of chlorine. 

2. The process of claim 1 wherein said thermoplastic alkenyl aromatic resin is, in chemically combined form, at least about 40 percent by weight of at least one alkenyl aromatic compound having the general formula:
 3. The process of claim 2 wherein said thermoplastic alkenyl aromatic resin is selected from the group consisting of: polystyrene, a copolymer of styrene and acrylonitrile, and an acrylonitrile- butadiene-styrene polymer.
 4. The process of claim 1 wherein the chlorinated olefin polymer is chlorinated polyethylene.
 5. The process of claim 4 wherein the chlorinated polyethylene has a molecular weight of from about 20,000 and 300,000 and has a crystallinity of less than about 10 percent when containing about 34 or more weight percent of chlorine. 